• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.04a
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• pp.49-53
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• 1997

In this paper, YbBa$_{2}$Cu$_{3}$O$_{x}$ superconductor was sintered by means of conventional solid reaction and the textured YbBa$_{2}$Cu$_{3}$O$_{x}$ was prepared by the Melted-Condensed Process in which SmBa$_{2}$Cu$_{3}$O$_{x}$ crystal was used as seed crystal to introduce the YbBa$_{2}$Cu$_{3}$O$_{x}$ crystal growth. The texture of YbBa$_{2}$Cu$_{3}$O$_{x}$ was examined by X-ray diffraction, and the fracture of YbBa$_{2}$Cu$_{3}$O$_{x}$ sample was observed by SEM, which proved the sample was well oriented. After oxygen absorption of the textured YbBa$_{2}$Cu$_{3}$O$_{x}$ sample, it's critical temperature was measureed to be 86K.eed to be 86K.

• Proceedings of the Materials Research Society of Korea Conference
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• 1996.11a
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• pp.174-176
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• 1996

In the YBCO matrix, 10wt.% Y$_2$BaCuO$\_$5/ (211 phase) was added, the final 211 content of YBCO made by MTG process could reach about 20wt.% which was the optimum value for the critical current density. And also 10wt.% Ag was added in the matrix of YBCO, which was nearly about the saturate solubility of silver in textured YBCO. SmBaCuO crystal was grown by the melted-condensed process. A 5${\times}$5${\times}$2㎣ single crystal of SmBaCuO was used to be the seed in the preparation of YBCO. It was proved the orientation of YBCO was the same as the orientation of the SmBaCuO seed. The oxygen absorption of bulk oriented YBCO was studied and the heat treatment of oxygen absorption would be in flowing oxygen, at 400$^{\circ}C$ for about 24 hours. the magnetic hysteresis loops were measured by Vibrating Smaple Magnetometer and the J$\_$c/ was calcuated by means of Bean's model.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.913-916
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• 2001

From 1994 the cooperation between NEU of China and MJU of South Korea for study of ReBaCuO (Re=Rare earth elements) superconductors has been carried out. The progress has been got in following projects. Critical current density ($J_c$) of YBaCuO superconductor prepared by Melting Textured Growth (MTG) was improved. In the preparation of textured YBaCuO, 20 wt.% of YBaCuO 211 phase was added, which would be climactic for the microcracks in the textured YBaCuO. The effects of the 211 phase and Ag content on the superconductivity were studied and discussed in detail. The improved $J_c$ value was reached to 8$\times$10^4 A/cm^2 (77K,0T). Single phase $YbBa_{2}Cu_{3}O_{x}$ superconductor was sintered by the traditional powder metallurgical method, and its reaction process was studied. In recent years, NdBaCuO superconductor is being performed. The behavior of $Nd_{4}Ba_{2}Cu_{2}O_{10}$(Nd422 phase) and the solid solubility, x in the superconductor $Nd_{1+x}Ba_{2-x}Cu_{3}O_{y}$ by the heat treatment in the low oxygen partial pressure (1%) or Ar at $950{\circ}C$ were investigated. The zone-melting process was used to make oriented NdBaCuO superconductor in order to increase the critical current density.